Mobile terminals using cellular networks often experience interference from various sources or due to various causes, such as interference caused by the same signal arriving at the mobile terminal at slightly different times after having propagated along different paths, i.e. so-called multi-path interference. As well-known, it is often possible to cancel interfering signals at a receiver, and the prior art teaches various methods of interference cancellation (IC), both at mobile terminals and at base stations. Mobile terminals often implement so-called single antenna interference cancellation (SAIC) algorithms, since physical constraints make it difficult to use more than one antenna in providing IC.
According to the prior art, conventional single signal channel estimation methods in SAIC receivers suffer significantly in the presence of co-channel interference. It is known that the joint channel estimation technique provides much better estimates since it also takes the interfering signal into account. However, it requires known overlapping bit sequences of the desired and interfering signals. This can be guaranteed by synchronized base stations so that the delay offset at the mobile receiver is no more than a few symbols. Moreover, separate known training sequences for the co-channel signals are required. Thus the prior art does not teach how to use joint channel estimation if the interfering training sequences are unknown or if the co-channel signals are asynchronous. Using joint channel estimation with these types of signals is needed for improving interfering signal suppression and for expanding SAIC receivers to multistage equalization structures.